topic Re: Mirroring question in Operating System - HP-UX

Mirroring question

Sean OB_1 — Tue, 03 Dec 2002 15:04:58 GMT

If I have a 12 disk lun (raid 5) in a FC60 array, and have the entire lun mirrored to a SC30 array, will the system continue to run if I lose a controller (2 disks) in the FC60?

My assumption is that the system will run off the mirror until the controller is back online and then I can resync the mirror.

Can someone verify that this is indeed how it will work?

TIA

Re: Mirroring question

Bill McNAMARA_1 — Tue, 03 Dec 2002 15:11:39 GMT

If you lose 2 disks in a raid group the data is not accessible. The mirror will switch after the pv timeout specified byu the pvdisplay timeout property of the lun and the alternate path of the PV (ie the mirror) in the VG. Why not stick with R1/0 on the FC60.

Later,
Bill

Re: Mirroring question

Bill McNAMARA_1 — Tue, 03 Dec 2002 15:13:26 GMT

is the FC60 in full or split bus mode btw.. if the disks haven't failed, ie just the controller, you should be able to access the lun via the remaining controller. In this case the Alternate path will be through the remaining Controller...a third alternate in that case would be the SC30 (FC30??)

Later,
Bill

Re: Mirroring question

Sean OB_1 — Tue, 03 Dec 2002 15:21:36 GMT

Bill,

the client wants the primary to be on a raid set in one building, and mirrored to another array in a different building.

The other building also has the failover service guard server.

My concern is that having a 12 disk lun in the FC60 means that if I lose one drawer I'll lose 2 disks in the lun, which means I lose data.

I'll have the alternate path setup to go through the second channel anyway, but I want to cover my bases in the unlikely event that I lose 2 disks at once in the FC60 lun.

Re: Mirroring question

Bill McNAMARA_1 — Tue, 03 Dec 2002 15:38:23 GMT

You can add as many alternates as you like, and in the case that 2 disks fail, you'll switch to the 2nd alternate.. ie on the other array..
I'd test it first though, there'd more than likely be a timout too large for comfort...

Later,
Bill